Most preferred process for WCDMA applications

Hi,

For PA in WCDMA applications, which process is more preferrd, CMOS, SiGe HBT or GaAs?

What are the today trend for modulation schemes and spec for WCDMA?

Thanks

Any link that enable me to do my finding?

GaAs is the most suitable for a linear and efficient RF power amplifier. But in the same time is the most expensive process.

Most of the WCDMA PA?s on the market still use a standard linear amplification, and sometimes using adaptive bias or a DC/DC converter on Vcc to improuve the efficiency at low power.

It seems that only SiliconLabs release a commercial PA with CMOS, besides, it's a nonlinear one.....
Since the square characteristics if I-V, the linearity of cmos PA is quite bad so that it's not suitable for WCDMA......

For a stand-alone PA, maybe the GaAs is the most mature one.

The advantage of SiGe BiCMOS is that it can be integrated with other blocks(transceiver/baseband...)

yeah till now , all the WCDMA PA is GaAs
check the RFMD , Anadigics , and Triquent

khouly